Methods and systems pertaining to preventing the corruption of filter coefficients
due to near end speech in an echo canceller that uses an adaptive filter to create
a local replica of an echo signal are provided. In accordance with a preferred
method, a far end signal is received and the presence of near end speech is indicated.
A filter coefficient vector is updated, and copies of the filter coefficient vector
are periodically stored. A stored copy of the filter coefficient vector is recovered
for use in the echo canceller. Further, an improved echo canceller that prevents
the corruption of filter coefficients due to near end speech, having a near end
speech indicator, a first buffer, a filter, and a second buffer connected to the
filter, is provided. The first buffer receives a far end signal. The filter is
responsive to the first buffer and the near end speech indicator. The filter includes
a filter coefficient vector generator, wherein the generator generates, updates,
and provides copies of filter coefficient vectors. The second buffer is connected
to the filter and stores the copies of the filter coefficient vectors for restoration
to the filter.